Led by Dr. Prabhat Jha, the research found that rates of dying from ischaemic heart disease - cardiac issues caused by a narrowing of the heart's arteries - in populations aged 30 to 69 increased rapidly in rural areas of India and surpassed those in urban areas between the year 2000 and 2015.

In contrast, the probability of dying from stroke decreased overall, but increased in India's northeastern states, where a third of premature stroke deaths occurred and only one sixth of the population lives. In these states, deaths due to stroke were about three times higher than the national average.

"The finding that cardiac disease rose nationally in India and that stroke rose in some states was surprising," said Dr. Jha. "This study also unearthed an important fact for prevention of death due to cardiovascular disease. Most deaths were among people with a previously known cardiac disease, and at least half were not taking any regular medications."

Dr. Jha and his team also showed that younger adults, especially those born after 1970, have the highest rate of death due to heart problems caused by narrowing of the heart's arteries.

Cardiovascular disease, comprising mostly of ischaemic heart failure and stroke, is the leading cause of death worldwide. Until now, most of the evidence of cardiovascular mortality in India has come from small, local studies or from imprecise modelling exercises.

"This work equips us with more detailed information that we couldn't have predicted based on earlier studies," said Dr. Jha. "Making progress in fighting the leading cause of death in India is necessary for making progress at the global level," Dr. Jha said. "We demonstrated the unexpected patterns of heart attack and stroke deaths. Both conditions need research and action if the world is going to achieve the United Nations Sustainable Development Goal of reducing cardiovascular mortality by 2030."